#app {
  font-family: Avenir, Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-align: center;
  color: #2c3e50;
  padding:0px;
  width:85%;
  margin: 0px auto -20px;
  background: rgb(209, 224, 220);
  /* 高度至少是整个可见屏幕高度的100% */
  min-height:100vh;
}
body{
  /* 背景图案地址 */
  background-image: url('./assets/6.jpg');
  /* 填满整个窗口 */
  background-size: cover;
}
